On domain of Poisson operators and factorization for divergence form elliptic operators

We consider second order uniformly elliptic operators of divergence form in R^{d + 1} whose coefficients are independent of one variable. For such a class of operators we establish a factorization into a product of first order operators related with Poisson operators and Dirichlet–Neumann maps. Consequently, we obtain a solution formula for the inhomogeneous elliptic boundary value problem in the half space, which is useful to show the existence of solutions in a wider class of inhomogeneous data. We also establish L² solvability of boundary value problems for a new class of the elliptic operators.